Peel the apples, core them and cut them into a large dice. In a large bowl, combine the diced apples, lemon juice, cinnamon, pumpkin or apple spice, sugar, vanilla, apple juice and cornstarch until evenly mixed. Pour into a 6-quart or larger Instant Pot.
In the same bowl, make the topping. Combine the flour, brown sugar, salt, cinnamon and oats. Add the butter and rub with your fingers until coarse crumbs form. Pour over the apples in an even layer.
Lock the lid and set the pressure valve to seal. Cook on high pressure for 1 minute. Quick release the pressure until all the steam has escaped and the lid unlocks. Carefully open the lid and serve the apple crisp with either whipped cream or ice cream.